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micropython/py/builtinimport.c
Damien George 1831034be1 py: Allow lexer to raise exceptions during construction. 
This patch refactors the error handling in the lexer, to simplify it (ie
reduce code size).

A long time ago, when the lexer/parser/compiler were first written, the
lexer and parser were designed so they didn't use exceptions (ie nlr) to
report errors but rather returned an error code.  Over time that has
gradually changed, the parser in particular has more and more ways of
raising exceptions.  Also, the lexer never really handled all errors without
raising, eg there were some memory errors which could raise an exception
(and in these rare cases one would get a fatal nlr-not-handled fault).

This patch accepts the fact that the lexer can raise exceptions in some
cases and allows it to raise exceptions to handle all its errors, which are
for the most part just out-of-memory errors during construction of the
lexer.  This makes the lexer a bit simpler, and also the persistent code
stuff is simplified.

What this means for users of the lexer is that calls to it must be wrapped
in a nlr handler.  But all uses of the lexer already have such an nlr
handler for the parser (and compiler) so that doesn't put any extra burden
on the callers.
2017-03-14 11:52:05 +11:00

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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
* Copyright (c) 2014 Paul Sokolovsky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "py/nlr.h"
#include "py/compile.h"
#include "py/objmodule.h"
#include "py/persistentcode.h"
#include "py/runtime.h"
#include "py/builtin.h"
#include "py/frozenmod.h"
#if 0 // print debugging info
#define DEBUG_PRINT (1)
#define DEBUG_printf DEBUG_printf
#else // don't print debugging info
#define DEBUG_PRINT (0)
#define DEBUG_printf(...) (void)0
#endif
#define PATH_SEP_CHAR '/'
bool mp_obj_is_package(mp_obj_t module) {
mp_obj_t dest[2];
mp_load_method_maybe(module, MP_QSTR___path__, dest);
return dest[0] != MP_OBJ_NULL;
}
// Stat either frozen or normal module by a given path
// (whatever is available, if at all).
STATIC mp_import_stat_t mp_import_stat_any(const char *path) {
#if MICROPY_MODULE_FROZEN
mp_import_stat_t st = mp_frozen_stat(path);
if (st != MP_IMPORT_STAT_NO_EXIST) {
return st;
}
#endif
return mp_import_stat(path);
}
STATIC mp_import_stat_t stat_file_py_or_mpy(vstr_t *path) {
mp_import_stat_t stat = mp_import_stat_any(vstr_null_terminated_str(path));
if (stat == MP_IMPORT_STAT_FILE) {
return stat;
}
#if MICROPY_PERSISTENT_CODE_LOAD
vstr_ins_byte(path, path->len - 2, 'm');
stat = mp_import_stat_any(vstr_null_terminated_str(path));
if (stat == MP_IMPORT_STAT_FILE) {
return stat;
}
#endif
return MP_IMPORT_STAT_NO_EXIST;
}
STATIC mp_import_stat_t stat_dir_or_file(vstr_t *path) {
mp_import_stat_t stat = mp_import_stat_any(vstr_null_terminated_str(path));
DEBUG_printf("stat %s: %d\n", vstr_str(path), stat);
if (stat == MP_IMPORT_STAT_DIR) {
return stat;
}
// not a directory, add .py and try as a file
vstr_add_str(path, ".py");
return stat_file_py_or_mpy(path);
}
STATIC mp_import_stat_t find_file(const char *file_str, uint file_len, vstr_t *dest) {
#if MICROPY_PY_SYS
// extract the list of paths
mp_uint_t path_num;
mp_obj_t *path_items;
mp_obj_list_get(mp_sys_path, &path_num, &path_items);
if (path_num == 0) {
#endif
// mp_sys_path is empty, so just use the given file name
vstr_add_strn(dest, file_str, file_len);
return stat_dir_or_file(dest);
#if MICROPY_PY_SYS
} else {
// go through each path looking for a directory or file
for (mp_uint_t i = 0; i < path_num; i++) {
vstr_reset(dest);
mp_uint_t p_len;
const char *p = mp_obj_str_get_data(path_items[i], &p_len);
if (p_len > 0) {
vstr_add_strn(dest, p, p_len);
vstr_add_char(dest, PATH_SEP_CHAR);
}
vstr_add_strn(dest, file_str, file_len);
mp_import_stat_t stat = stat_dir_or_file(dest);
if (stat != MP_IMPORT_STAT_NO_EXIST) {
return stat;
}
}
// could not find a directory or file
return MP_IMPORT_STAT_NO_EXIST;
}
#endif
}
#if MICROPY_ENABLE_COMPILER
STATIC void do_load_from_lexer(mp_obj_t module_obj, mp_lexer_t *lex) {
#if MICROPY_PY___FILE__
qstr source_name = lex->source_name;
mp_store_attr(module_obj, MP_QSTR___file__, MP_OBJ_NEW_QSTR(source_name));
#endif
// parse, compile and execute the module in its context
mp_obj_dict_t *mod_globals = mp_obj_module_get_globals(module_obj);
mp_parse_compile_execute(lex, MP_PARSE_FILE_INPUT, mod_globals, mod_globals);
}
#endif
#if MICROPY_PERSISTENT_CODE_LOAD || MICROPY_MODULE_FROZEN_MPY
STATIC void do_execute_raw_code(mp_obj_t module_obj, mp_raw_code_t *raw_code) {
#if MICROPY_PY___FILE__
// TODO
//qstr source_name = lex->source_name;
//mp_store_attr(module_obj, MP_QSTR___file__, MP_OBJ_NEW_QSTR(source_name));
#endif
// execute the module in its context
mp_obj_dict_t *mod_globals = mp_obj_module_get_globals(module_obj);
// save context
mp_obj_dict_t *volatile old_globals = mp_globals_get();
mp_obj_dict_t *volatile old_locals = mp_locals_get();
// set new context
mp_globals_set(mod_globals);
mp_locals_set(mod_globals);
nlr_buf_t nlr;
if (nlr_push(&nlr) == 0) {
mp_obj_t module_fun = mp_make_function_from_raw_code(raw_code, MP_OBJ_NULL, MP_OBJ_NULL);
mp_call_function_0(module_fun);
// finish nlr block, restore context
nlr_pop();
mp_globals_set(old_globals);
mp_locals_set(old_locals);
} else {
// exception; restore context and re-raise same exception
mp_globals_set(old_globals);
mp_locals_set(old_locals);
nlr_jump(nlr.ret_val);
}
}
#endif
STATIC void do_load(mp_obj_t module_obj, vstr_t *file) {
#if MICROPY_MODULE_FROZEN || MICROPY_PERSISTENT_CODE_LOAD || MICROPY_ENABLE_COMPILER
char *file_str = vstr_null_terminated_str(file);
#endif
// If we support frozen modules (either as str or mpy) then try to find the
// requested filename in the list of frozen module filenames.
#if MICROPY_MODULE_FROZEN
void *modref;
int frozen_type = mp_find_frozen_module(file_str, file->len, &modref);
#endif
// If we support frozen str modules and the compiler is enabled, and we
// found the filename in the list of frozen files, then load and execute it.
#if MICROPY_MODULE_FROZEN_STR
if (frozen_type == MP_FROZEN_STR) {
do_load_from_lexer(module_obj, modref);
return;
}
#endif
// If we support frozen mpy modules and we found a corresponding file (and
// its data) in the list of frozen files, execute it.
#if MICROPY_MODULE_FROZEN_MPY
if (frozen_type == MP_FROZEN_MPY) {
do_execute_raw_code(module_obj, modref);
return;
}
#endif
// If we support loading .mpy files then check if the file extension is of
// the correct format and, if so, load and execute the file.
#if MICROPY_PERSISTENT_CODE_LOAD
if (file_str[file->len - 3] == 'm') {
mp_raw_code_t *raw_code = mp_raw_code_load_file(file_str);
do_execute_raw_code(module_obj, raw_code);
return;
}
#endif
// If we can compile scripts then load the file and compile and execute it.
#if MICROPY_ENABLE_COMPILER
{
mp_lexer_t *lex = mp_lexer_new_from_file(file_str);
do_load_from_lexer(module_obj, lex);
return;
}
#endif
// If we get here then the file was not frozen and we can't compile scripts.
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError,
"script compilation not supported"));
}
STATIC void chop_component(const char *start, const char **end) {
const char *p = *end;
while (p > start) {
if (*--p == '.') {
*end = p;
return;
}
}
*end = p;
}
mp_obj_t mp_builtin___import__(size_t n_args, const mp_obj_t *args) {
#if DEBUG_PRINT
DEBUG_printf("__import__:\n");
for (mp_uint_t i = 0; i < n_args; i++) {
DEBUG_printf(" ");
mp_obj_print(args[i], PRINT_REPR);
DEBUG_printf("\n");
}
#endif
mp_obj_t module_name = args[0];
mp_obj_t fromtuple = mp_const_none;
mp_int_t level = 0;
if (n_args >= 4) {
fromtuple = args[3];
if (n_args >= 5) {
level = MP_OBJ_SMALL_INT_VALUE(args[4]);
}
}
mp_uint_t mod_len;
const char *mod_str = mp_obj_str_get_data(module_name, &mod_len);
if (level != 0) {
// What we want to do here is to take name of current module,
// chop <level> trailing components, and concatenate with passed-in
// module name, thus resolving relative import name into absolue.
// This even appears to be correct per
// http://legacy.python.org/dev/peps/pep-0328/#relative-imports-and-name
// "Relative imports use a module's __name__ attribute to determine that
// module's position in the package hierarchy."
level--;
mp_obj_t this_name_q = mp_obj_dict_get(MP_OBJ_FROM_PTR(mp_globals_get()), MP_OBJ_NEW_QSTR(MP_QSTR___name__));
assert(this_name_q != MP_OBJ_NULL);
#if MICROPY_CPYTHON_COMPAT
if (MP_OBJ_QSTR_VALUE(this_name_q) == MP_QSTR___main__) {
// This is a module run by -m command-line switch, get its real name from backup attribute
this_name_q = mp_obj_dict_get(MP_OBJ_FROM_PTR(mp_globals_get()), MP_OBJ_NEW_QSTR(MP_QSTR___main__));
}
#endif
mp_map_t *globals_map = &mp_globals_get()->map;
mp_map_elem_t *elem = mp_map_lookup(globals_map, MP_OBJ_NEW_QSTR(MP_QSTR___path__), MP_MAP_LOOKUP);
bool is_pkg = (elem != NULL);
#if DEBUG_PRINT
DEBUG_printf("Current module/package: ");
mp_obj_print(this_name_q, PRINT_REPR);
DEBUG_printf(", is_package: %d", is_pkg);
DEBUG_printf("\n");
#endif
mp_uint_t this_name_l;
const char *this_name = mp_obj_str_get_data(this_name_q, &this_name_l);
const char *p = this_name + this_name_l;
if (!is_pkg) {
// We have module, but relative imports are anchored at package, so
// go there.
chop_component(this_name, &p);
}
uint dots_seen = 0;
while (level--) {
chop_component(this_name, &p);
dots_seen++;
}
if (dots_seen == 0 && level >= 1) {
// http://legacy.python.org/dev/peps/pep-0328/#relative-imports-and-name
// "If the module's name does not contain any package information
// (e.g. it is set to '__main__') then relative imports are
// resolved as if the module were a top level module, regardless
// of where the module is actually located on the file system."
// Supposedly this if catches this condition and resolve it properly
// TODO: But nobody knows for sure. This condition happens when
// package's __init__.py does something like "import .submod". So,
// maybe we should check for package here? But quote above doesn't
// talk about packages, it talks about dot-less module names.
DEBUG_printf("Warning: no dots in current module name and level>0\n");
p = this_name + this_name_l;
} else if (level != -1) {
mp_raise_msg(&mp_type_ImportError, "invalid relative import");
}
uint new_mod_l = (mod_len == 0 ? (size_t)(p - this_name) : (size_t)(p - this_name) + 1 + mod_len);
char *new_mod = alloca(new_mod_l);
memcpy(new_mod, this_name, p - this_name);
if (mod_len != 0) {
new_mod[p - this_name] = '.';
memcpy(new_mod + (p - this_name) + 1, mod_str, mod_len);
}
qstr new_mod_q = qstr_from_strn(new_mod, new_mod_l);
DEBUG_printf("Resolved base name for relative import: '%s'\n", qstr_str(new_mod_q));
if (new_mod_q == MP_QSTR_) {
mp_raise_msg(&mp_type_ValueError, "cannot perform relative import");
}
module_name = MP_OBJ_NEW_QSTR(new_mod_q);
mod_str = new_mod;
mod_len = new_mod_l;
}
// check if module already exists
qstr module_name_qstr = mp_obj_str_get_qstr(module_name);
mp_obj_t module_obj = mp_module_get(module_name_qstr);
if (module_obj != MP_OBJ_NULL) {
DEBUG_printf("Module already loaded\n");
// If it's not a package, return module right away
char *p = strchr(mod_str, '.');
if (p == NULL) {
return module_obj;
}
// If fromlist is not empty, return leaf module
if (fromtuple != mp_const_none) {
return module_obj;
}
// Otherwise, we need to return top-level package
qstr pkg_name = qstr_from_strn(mod_str, p - mod_str);
return mp_module_get(pkg_name);
}
DEBUG_printf("Module not yet loaded\n");
uint last = 0;
VSTR_FIXED(path, MICROPY_ALLOC_PATH_MAX)
module_obj = MP_OBJ_NULL;
mp_obj_t top_module_obj = MP_OBJ_NULL;
mp_obj_t outer_module_obj = MP_OBJ_NULL;
uint i;
for (i = 1; i <= mod_len; i++) {
if (i == mod_len || mod_str[i] == '.') {
// create a qstr for the module name up to this depth
qstr mod_name = qstr_from_strn(mod_str, i);
DEBUG_printf("Processing module: %s\n", qstr_str(mod_name));
DEBUG_printf("Previous path: =%.*s=\n", vstr_len(&path), vstr_str(&path));
// find the file corresponding to the module name
mp_import_stat_t stat;
if (vstr_len(&path) == 0) {
// first module in the dotted-name; search for a directory or file
stat = find_file(mod_str, i, &path);
} else {
// latter module in the dotted-name; append to path
vstr_add_char(&path, PATH_SEP_CHAR);
vstr_add_strn(&path, mod_str + last, i - last);
stat = stat_dir_or_file(&path);
}
DEBUG_printf("Current path: %.*s\n", vstr_len(&path), vstr_str(&path));
if (stat == MP_IMPORT_STAT_NO_EXIST) {
#if MICROPY_MODULE_WEAK_LINKS
// check if there is a weak link to this module
if (i == mod_len) {
mp_map_elem_t *el = mp_map_lookup((mp_map_t*)&mp_builtin_module_weak_links_map, MP_OBJ_NEW_QSTR(mod_name), MP_MAP_LOOKUP);
if (el == NULL) {
goto no_exist;
}
// found weak linked module
module_obj = el->value;
} else {
no_exist:
#else
{
#endif
// couldn't find the file, so fail
if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
mp_raise_msg(&mp_type_ImportError, "module not found");
} else {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError,
"no module named '%q'", mod_name));
}
}
} else {
// found the file, so get the module
module_obj = mp_module_get(mod_name);
}
if (module_obj == MP_OBJ_NULL) {
// module not already loaded, so load it!
module_obj = mp_obj_new_module(mod_name);
// if args[3] (fromtuple) has magic value False, set up
// this module for command-line "-m" option (set module's
// name to __main__ instead of real name).
if (i == mod_len && fromtuple == mp_const_false) {
mp_obj_module_t *o = MP_OBJ_TO_PTR(module_obj);
mp_obj_dict_store(MP_OBJ_FROM_PTR(o->globals), MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR___main__));
#if MICROPY_CPYTHON_COMPAT
// Store module as "__main__" in the dictionary of loaded modules (returned by sys.modules).
mp_obj_dict_store(MP_OBJ_FROM_PTR(&MP_STATE_VM(mp_loaded_modules_dict)), MP_OBJ_NEW_QSTR(MP_QSTR___main__), module_obj);
// Store real name in "__main__" attribute. Choosen semi-randonly, to reuse existing qstr's.
mp_obj_dict_store(MP_OBJ_FROM_PTR(o->globals), MP_OBJ_NEW_QSTR(MP_QSTR___main__), MP_OBJ_NEW_QSTR(mod_name));
#endif
}
if (stat == MP_IMPORT_STAT_DIR) {
DEBUG_printf("%.*s is dir\n", vstr_len(&path), vstr_str(&path));
// https://docs.python.org/3/reference/import.html
// "Specifically, any module that contains a __path__ attribute is considered a package."
mp_store_attr(module_obj, MP_QSTR___path__, mp_obj_new_str(vstr_str(&path), vstr_len(&path), false));
size_t orig_path_len = path.len;
vstr_add_char(&path, PATH_SEP_CHAR);
vstr_add_str(&path, "__init__.py");
if (stat_file_py_or_mpy(&path) != MP_IMPORT_STAT_FILE) {
//mp_warning("%s is imported as namespace package", vstr_str(&path));
} else {
do_load(module_obj, &path);
}
path.len = orig_path_len;
} else { // MP_IMPORT_STAT_FILE
do_load(module_obj, &path);
// This should be the last component in the import path. If there are
// remaining components then it's an ImportError because the current path
// (the module that was just loaded) is not a package. This will be caught
// on the next iteration because the file will not exist.
}
}
if (outer_module_obj != MP_OBJ_NULL) {
qstr s = qstr_from_strn(mod_str + last, i - last);
mp_store_attr(outer_module_obj, s, module_obj);
}
outer_module_obj = module_obj;
if (top_module_obj == MP_OBJ_NULL) {
top_module_obj = module_obj;
}
last = i + 1;
}
}
// If fromlist is not empty, return leaf module
if (fromtuple != mp_const_none) {
return module_obj;
}
// Otherwise, we need to return top-level package
return top_module_obj;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin___import___obj, 1, 5, mp_builtin___import__);
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